Method of and machine for making spiral fin tubing



Oct. 25, 1932. G. H. PICKHARD f 1,884,203

METHOD OF AND MACHINE FOR MAKING SPIRAL FIN TUBING Filed April 2. 1928 4 shams-sheet 1 vll I @wm anmmu H Gear e/Yp/'ck/Iard 1-1 y Oct. 25, 1932. G. H. PICKHARD METHOD OF AND MACHINE FOR MAKING SPIRAL FIN YTUBING Filed April 2, 1928 4 Sheets-Sheet 2 nvanoz Geo/32H @fC/Maid.

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Oct. 25, 1932. G. H. PICKHARD 1,884,203

' METHOD OF AND MACHINE FOR MAKING SPIRAL FIN TUABING FiledV April z. 1915.8 4 sheets-sheet 4 @l mn 0 lllllA Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE GEORGE H. PICKHARD, OF DETROIT, MICHIGAN, ASSIGNOR TO MCCORD RADIATOR & MFG. C0., F DETItOIT, MICHIGAN, A CORPORATION OF MAINE lMETHOD 0F AND MACHINE FOR MAKING SPIRAL FIN TUBING Application filed April 2, 1928. Serial No. 266,488.

This invention relates to a method of andl machine for making spiral fin tubing.

1One object of my invention is to provide a machine for spirally winding a continuous flat sheet metal fin strip on a tube Without displacing the sides of the strip out of the spiral path of the st ripabout the tube thereby permitting more convolutions of iin strip material to be wound on a given length of tube to obtain greater radiating surface than possible with a corrugated in strip, as heretofore.

Another obj ect of my invention to provide means for so changing the cross-sectional shape of the' iinstrip as it is presented to the tube that the strip may be spirally wound on the tube without stretching of the strip and thus keep the strip rigid and stiff to resist strains and stress which would otherwise bend and break down.

A further object of my invention is to provide a machine which is simple in construction and operation and which will produce a regular anduniform product rapidly, continuously, smoothly, and economically.

The invention consists further in the product produced by my improved method and machine and also in the matters hereinafter described and claimed.

In the accompanying drawings- Fig. 1 is a front view of the machine of my invention;

Fig. 2 is a sectional view of a detail of construction taken on line 2--2 of Fig. 1;

Fig. 3 shows how the winding operation is initially begun;

Fig. 4 is an enlarged vertically longitudinal sectional view taken through the machine en line 4-4 of Fig. 1;

Fig. 5 is a transverse vertical sectional view taken on line 5--5 of Fig. 4;

Fig. 6 is a horizontal sectional View taken on line 6-6 .of Fig. 5;

Fig. 7 is a vertical sectional view taken'on line 7-7 of Fig. 4; y

Fig. 8 is a vertical longitudinal sectional View taken through the machine 'at the winding station; vand Fig. 9 is a perspective view of a tube with a strip wound thereon.

The machine of my. invention has a horizontal bed or base 1 similar to that as employed for metal-turning lathes. Mounted on the top of the bed are the tube feeding and strip winding assemblies of the machine.

The tube feeding assembly comprises a pair of upright end plates 2, 2 arranged crosswise of the bed and secured to the same, kone in advance of the other, by cap screws 3, 3, as shown in Figs. 1 and 5. The plates 2 are tied together by bolts 4, 4 provided with spacers 5, 5 for keeping the plates apart, as shown in Fig. 4. A drum 6 is revolutionally mounted between the plates 2 on anti-friction bearing rollers 7, 7 confined in annular raceways formed between the ends of the drum and inwardly extending -portions 8, 8 on the plates. The outer ends of the race-ways are closed by the plates 2 while their inner ends are closed by rings 9, 9 which are secured by screws 10, 10 to-the annular portions 8 of the respective plates 2, as shown in Figs. 4 and 5.

A horizontal shaft 11 ext-ends through and beyond the plates 2, 2 on opposite sides thereof and is journaled at its ends in suitable bearings 12, 13, the former being at the forward end of the shaft and supported by a bracket 14 cast integral with and extending forward from the front plate 2, as shown in Fig. 4. The rear bearing 13 is at the upper end of a standard 15, which is secured to and extends upward from the base 1 to the reariof the rear plate 2. Shaft `11 also extends through the center of the dlium 6 and the latter is fixed theretofas at 16 and 17, respectively,'so that the drum will turn with the shaft when the latter is rotated. To accomplish this, a belt pulley,18 is loose on the shaft 11 in the space. between the rear plate 2 and the standard 15. The pulley 18 is provided on its rear side with an annular clutch flange 19 with which cooperatesa friction cone member 20 splined on `the shaft 11 and movable into and out of en- 'gageinent with said ange through ahandl operated shift-yoke (not shown) whlch engages in a groove 21 in the hub of said membe r. The tube 22 to be operated on is fed endwise through the machine through the shaft 11 which is made hollow to receive and guide y surfaces of the rolls are concaved to conformv to and engage the outside of the tube andjthese surfaces are roughened by milling so as not to slip on the tube and thus feed it through the. machine when the rolls are revolved in the direction indicated by the arrows in Fig. 6. The rolls are splined on shafts 25, 25 journaled in the drum 6 and are arranged one for each pair of rolls. The rolls 23, 24 are yieldably/ held against the tube 22 by coiled springs 26, 26 arranged on the outer sides of the rolls and retained in place by channel shape retainer rings 27, 27 which are pinned on the respective shafts 25, 25, as shown. The spring 26 allows the rolls 23, 24 to yield laterally as the tube 22 passes between them and thus compensate for any irregularities that might be on the surface or in the shape of the tube. Thus, the tube 22 may be fed through the machine without putting any lateral strain on the feed rolls.

The rotation of the feed rolls 23, 24 is effected through the turning of the drum 6 by the shaft 11. This is accomplished by fixing worm pinions 28, 28 on the opposite ends of the shafts 25, 25 and having said pinions mesh with worms 29, 29 on worm shafts 30, 30. These arej ournaled in the drum 6 and have at their forward ends planet gears 31, 31 which mesh with and travel around a fixed or stationary sun gear 32 fixedy in the front plate 2 by a nut 33, as shown in Fig. 4. W'ith concave periph-eries, the rolls 23, 24 engage about practically the entire circumference of thetube 22 I and thus rotate it on its axis as the rolls are carried bodily around with the drum 6. i The strip winding mechanism comprises a horizontal shaft 34 journaled in the bearing 12 above the shaft 11 and arranged substantially parallel therewith. A spurvgear35 is xed to the rear end of the shaft 34 and meshes with gear'teeth 36 cutin the portion of the shaft 11 at said gear so as'to rotate the same in the. turning of said shaft. The teeth 36 extend back through and beyond the sun gear 32 and provide the spline connection at 16 with the drum 6.

At the frontend of the shaft 34 is a radial flange 37 which extends inward toward the tube 22 over the front end of the shaft 11. The

rear face a of the flange 37 is beveled or in-r clined outward while the opposed end surface b of the shaft 11 is straight and at right angles to the tube 22, as 'shown in Figs. 4v and 8. This provides a triangular-like throat with the apex of the triangle at the outer end of the throat. g

The n material to be spirally wound on the tube 22 is in the form of a continuous sheet metal strip 38 which is drawn endwise into.

the throat from a supply roll 39 turnably vthe strip,

mounted on a bracket arm 40 secured to vone side of the bed or base 1 of the machine, as shown in Fig. 1. The width of the strip 38 as furnished to the machine is substantially the same as the height or distance that the strip when wound on the tube extends outward 'therefrom so that the strip need not be trimmed down for winding on the tube. The normal cross-sectional shape of the strip 38 as itis furnished to the machine is rectangular with parallel flat sides and of substantiallyy a uniform thickness throughout the width of as shown at c in Fig. 9. This thick ness is substantially the same as the width of the base of the triangular throat into which the strip is drawn in the winding operation.

As shown inv Fig. 1, the bearing 12 for the forward end of the shaft 11 is in the form of an upright block which is secured by cap screws 4l, 41 to the bracket 14 with the front face of the block flush with the front end of the bracket. A fiat guide plate 42 is secured to the front end of the bracket 14 by a screw 43 and extends inward over the front face of the block 12 toward the tube 22. 'The plate 42 is arranged on the side of the tube adjacent the supply roll 39 and the strip 38 is guided from said roll to the tube over the fiat front face of said plate. A guide bar 44 is secured to front face of the plate 42 and has a channel 45 therein to receive the strip 38 and guide it to the tube. The channel 45 conforms to the normal shape of the strip 38 and is long enough to straighten the strip as it is drawn to the tube. One form of securing the guide bar 44 to the plate 42 is shown in Figs. 1 and 2. As there illustrated, fastening strips 46, 46 overlap the rabbetted upper and lower edges of the guide bar and are secured to the plate 42 by screws 47, 47.

A guide plate 48 is secured by screws 49 to the front side of the block 12 on the side of the tube 22 opposite the guide bar 44. Plate 48 has a curved edge d in a Vertical plane extending part way around the circumference ward therefrom, as shown`in Fig. 3. The

upper end of edge d is opposite the entrance point of the strip 38 into the throat between flange 37 and shaft end b so as to be struck by the strip on being drawn into the throat and give the strip its initial curvature about th(1 tube in the starting of the machine. The shaft end b is spirallyk milled, as shown in Fig. 3, so as to grip the Hat side of the strip and as sist curved edge d infcurving the strip. After the strip 38 has taken several convolutions about the tube 22, the strip is then tight 0n the tube and the further drawing of the strip from the supply roll 39 is through the turn' ing of the tube by the rotation of the drum 6.

At the start of a winding operation, the end of the strip 38 is cut off at an angle, as at e in Fig. 3, before the strip end is inserted into the throat between flange 37 and shaft end Z). In so cutting the strip, it is given a pointed end so that there is no metal in the Way to interfere with the strip following around the curved edge d. On passing into this throat, the strip 38 is deformed by the squeezing action on the opposite flat sides ofthe strip and' its cross-sectional shape is changed from rectangular to triangular, as shown in Figs. 4 and 8. This squeezing action is merely along the outer half of the strip and effects a reduction of thickness of such portion with the tube is less than with a corrugated Vao strip, thereby giving greater radiating surface by permitting more strip material to be wound on a given length of tube by winding the convolutions of the strip closer together. Moreover, With a plain strip, it Will Withstand lto better advantage the edgewise and side strains when struck by exterior objects v as the body of the strip has not been weakened by any bending or stretching strains as heretofore. v

With the rolling action on the strip confined along its outer half, the inner half of the strip is not deformed with the result that crosssectional shape of such portion remains substantially the same as the original cross-sectional .shape of the strip. This provides an effective base for the strip at its contact with the tube and thus supports the strip against bending when struck on either side.

The forward endy of the shaft 34 is reduced and is supported in a bearing plate 50 secured by bolts 51 to the rear side of a bracket arm 52 which is fastened by a cap screw 53 on the upper side of the bearing block 12. Anti-friction bearing balls 54, 54 are suitably retained between the plate 50 and the adjacent front face of the fiange 37 so as to take care of the outward endfthrusts on said Harige as the strip 38 is 'squeezed thereby.

The machine is simple in. construction and operation and is highly eliicient. The tin strip material 38 is wound rapidly, smoothly, evenly and continuously on the tube. as the latter is rotated and fed past the winding assembly. The pitch of the wound strip on the tube is determined by the speed of the linear movement of the tube past the Winding sta# tion and this is regulated by the speed of rotation of the feed rolls 23, 24. In carrying these around bodily With the drum 6, the feed rolls also serve to rotate the tube so as to draw the strip 38 thereon. Thus, the feed and rotation of the tube is effected through a single set of rolls instead of two ysets as heretofore, thereby reducing the overall length 'and cost of construction of the drum head assembly by requiring fewer and less complicated parts.

The details of construction shown and described may be variously changed and modilied without departing from the spirit and sco e of my invention. The invention is not to e limited to tubes as rods could be substituted for tubes. This term as used in the claims is to be given a meaning. compreheni' sive enough to include rods or any other cylindric elements on which the strips are to be Wound.

I claim as my invention:

1. In amachine for making spiral lin tubing comprising in combination, means for supporting a tube, means for presenting a fiat sheet metal fin strip edgewise to the tube, and rotary means for reducing the thickness of the-strip along its outer edge portion as the strip is presented to the tube to compensate for the larger circumference around the outer edge of the strip as itis spirally Wound on the tube, said last named means while shaping the strip also forcing it about the tube.

2. In a machine for making spiral iin tubing, comprising in combination, means for rotating a tube andffeeding it through the machine, means for presenting a sheet metal fin stripedgewise to the tube, rotary members between which the strip is passed on being Wound on the tube, one of said members having an inclined surface to reduce the outer edge portion only of the strip as it is presented to the tube to compensate for the larger circumference about the outer .edge of the strip as it is Wound on the tube,

and means for rotatingsaid members with the tube in a direction to cause the same to force the strip about the tube. 3. In a machine for making spiral iin tub- .ing comprising in combination, means for presenting a liat sheet metal fin strip edgewise to a tube to Wind the lin strip spirally thereon as the tube is rotated and fed endwise through the machine, and means for rotating the tube and feeding it through the machine comprising, a single set of rolls engaging the tube, and means for carrying the -rolls bodily around the axis of the tube' for rotating the same and at the same time rotatin g the rolls in a direction to feed the tube through the machine, said rolls having concave peripheries to engage the tube about slbstantially the entire circumference thereo 4. In a machine for making spiral fin tubing comprising in combination, means for presenting a iiat .sheet metal lin strip edgewise to a tube to vind the iin strip spirally thereon as the tube is rotated and fed endwise through the machine, and means for rotating the tube and feeding it through the machine comprising, a rotary drum to receive the tube, a single set of rolls carried by the drum and engaging the tube for rotating the same in the turning of the drum, and means for rotating the rolls in the turning of the drum to feed the tube through the drum, said rolls having concave peripheries to engage the rtube about substantially the entire circumference thereof.

5. In a machine for making spiral fin tubing comprising in combination, means for presenting a flatI sheet metal fin strip edgewise to a tube to wind the fin strip spirally thereon as the tube is rotated and fed endwise through the machine, andl means for rotating the tube and feeding it through the machine comprising, a rotary drum to receive the tube, a single set of rolls carried by the drum and engaging the tube for rotating the same in the turning of the drum, and means including a planetary gearing for rotating the rolls in the turning of the drum` to feed the tube through the drum, said rolls having concave peripheries to engage the tube about substantially the entire circumference thereof. 4

6. In a machine for making spiral iin tubing comprising in combination, a hollow rotary shaft to receive and guide a tube, means for rotating the tube and feeding it through said shaft, means for presenting a Hat sheet metal fin stripedgewise to the tube across the end ofthe shaft where the tube leaves the same, a rotary member cooperating with the end of the shaft to press the strip against the same to reduce the thickness of the strip along its outer marginal portion to compensate for'the larger circumference around the outer edge of the strip as it is spirally wound on the tube, and means for rotating the shaft and member with the'tube in a direction to cause the shaft and the member while shaping the strip to force it about the tube.

7. In a machine for making spiral fin tubing comprising in combination, a hollow rotary shaft to receive and guide a tube, means for rotating the tube and feeding it through said shaft, means for presenting a fiat sheet metal fin strip edgewise to the tube across the end of the shaft where the tube leaves the same, and a. rotary member cooperating with the end of the shaft to press the strip against the same and having an inclined surface to reduce the thickness of the strip along its outer marginal portion to compensate for the larger circumference around the outer edge of the strip as it is spirally wound on the tube, said rotary member being rotated by the shaft in the rotation thereofrwith the tube to cause the shaft and the member while shaping the stripto force it about the tube.

8. In a machine for making spiral fin tubmetal fin strip edgewise to the tube, and power driven rotary means operating on the strip as it is presented to the tube in a manner to reduce vthe thickness of the strip along its outer marginal portion to compensate for the larger circumference around the outer edge of the strip as it is spirally wound on the tube, said rotary means While shaping the strip also forcing it about the tube. f

9. In a machine for making spiral iin tubing comprising means for rotating a tube and moving it endwise through the machine, means for presenting a iiat sheet metal En strip edgewise to the tube, and power driven rotary disclike members between which the strip is passed to the tube, said members acting to squeeze the strip laterally between them to reduce the thickness of the outer marginal portion of the strip to compensate for the larger circumference about the outer edge of the strip as it is spirally woundon the tube, said members whileshaping the strip also acting to force the strip about the tube.

l0. The method of making spiral fin tubing, which consists in rotating and longitudinally moving a tube past a strip winding station, presenting a flat sheet metal strip edgewise to the tube at said station, andiwhile presenting the strip to the tube at said station reducing'the thickness of the strip along its outer marginal portion by rotary forces which also serve to force the strip about the tube.

11. In a machine for making spiral fin tubing comprising in combination, means for supporting. a tube and moving it endwise through the machine, means for presenting a fiat sheet metal fin strip edgewise to the tube having a normal rectangular cross section, and power driven rotary means operating on the strip as it is presented to the tube in a manner to reduce the thickness of the strip along its outer marginal portion to compensate for the larger circumference around the outer edge of the strip as it is spirally wound around the tube, said rotary means while shaping the strip also forcing it about the tube.

l2. -In a machine for making spiral fin tubi ing comprising in combination means for presenting a flat sheet metal fin strip edgewise to a tube to wind the fin strip spirally thereon as the tube is rotated and fed endwise through the machine, and means for rotating a tube and feeding it through the machine comprising a rotary drum to receive the tube, a single set of rolls carried by the drum and engaging the tube for rotating the tube inthe turning of the drum, a stationary sun gear at one end of the drum and having a bore for the passage of the tube therethrough, planet gears in mesh with said sun gear and carried about the same 1n tte rotation of the drum, and means connccting the rolls with said planet gears for t turning the rollsto feed the tube through the planets for a tube to wind thefin stri drum in the rotation of the latter.

13. In a machine for making spiral fin tubing comprising in combination means for presenting a flat sheet metal lin strip edgewise to a tube to Wind the fin strip spirally thereon as the tube is rotated and fed endwise through the machine, and means for rotating the tube and feeding it through the machine comprising a rotary drum to receive the tube, a single set of rolls in the drum and engaging the tube, a stationary sun gear associated with the drum and having an axial passage for the tube, planet gears in mesh With said sun gear, transversely arranged shafts journaled in the drum and connected with the rolls and planet gears, respectively, and Worm gearing connecting the shafts of the rolls with those of the rotating the rolls in the turning of the drum. l

14. In a machine for making spiral fin tubing comprising in combination means for presenting a flat sheetmetal iin strip edgewise to a tube to Wind the lin strip spirally thereon as the tube is rotated and fed endwise through the machine,` and means for rotating the tube and feeding it through the machine comprising a hollow rotary shaft to receive Y.

the tube, a drum fixed to the shaft for rotation thereby, and a single set of rolls mounted in the drum and engaging the tube for rotating gud feeding the tube in the rotation of the rum.

15. In a machine for making spiral lin tubing comprising 1n combination means' for presenting a fiat sheet metal fin strip edgewise to p spirally thereon as the tube is rotated and fed eiidwise through the machine, and means for rotating the tube and feeding it through the machine comprising a rotary drum to receive the tube, shafts mounted in the drum on opposite sides of the tube, feed rolls splined on said shafts and engaging the tube, holding the rolls for rotating the shafts to turn the rolls in the rotation of the drum.

In testimony whereof I aiiix my signature.

' GEORGE H. PICKHARD.

springs means for yieldably against the tube, and means 

